Become a Member

According to an article written by NCDD Fellow Troy McKinney “Horizontal Gaze Nystagmus – How it Works – How to Challenge and Exclude It” it takes 82 seconds to correctly perform the HGN test.

False. NHTSA manuals are made available to NCDD members that can establish this fact and more.

Holding your breath can cause the result to increase. Experts that have published articles on this subject frequently offer assistance to NCDD members.

Credited to attorney and NCDD member Felipe Plascencia, the sale of the house analogy describes the trial as a house, the police officer as the owner, and the prosecutor as the real estate agent. The jury is the potential buyer of the house that the prosecution and police are attempting to convince to buy the house (which is represented to be in excellent condition). The defense attorney is the home inspector who discovers the faults and defects within the house. The faults and defects should create doubt in the minds of the buyers, who then issue a no sale verdict (i.e. not guilty verdict). This and many other techniques are taught to NCDD members through attendance at our NCDD seminars.

It has no effect on whole blood testing. However if serum testing is employed using an enzymatic assay method (such as EMIT) then the use of Ringer's lactate has been shown to cause false-positives or artificially increased alcohol results. the NCDD virtual library contains scientific articles that discuss this problem. By joining, an NCDD member receives access to these materials.

False. There is actually a range of reported ratios that published scientific articles report as low as 1.10 and as high as 1.50. Members can visit the NCDD virtual library for the materials.

Widmark's formula is used to determine a possible alcohol level at particular point in time using calculations based on factors such as weight, sex, amount of alcohol consumed, and times.
The formula is A= c x p x r:
A= amount of alcohol in body (grams)
C= blood alcohol concentration (mg/g)
P= body weight (kilograms)
R= rho (or Widmark factor) which is the volume of distribution of alcohol.

Found in the NHTSA DWI Detection and Standardized Field Sobriety Student Manuals, they are:
a. Vehicle in Motion
b. Personal Contact
c. Pre-arrest Screening

This question is based on NCDD member Lenny Stamm's published article entitled "THE TOP 20 MYTHS OF BREATH, BLOOD AND URINE TESTING". Click on the title to learn about all 20 myths. These and many other articles are made available to NCDD members at no additional cost.

A: The chemicals which are added to many blood samples taken by police, sodium fluoride and potassium oxalate, are salts. If too much is added, or the amount of blood placed into the tube is less than the desired amount, then the ratio of salt to blood can become too high. This can cause extra alcohol to leach into the air above the blood sample (i.e. headspace) in the blood vial. If the laboratory uses the headspace method of analysis, the results can become artificially high. Extra precautions must be taken by the lab to counter this phenomona. Dr. Alexander Robert Walker Forrest has written “it has been known for many years that the salting-out of Ethanol can occur in head space vials. For example, in 1983 AW Jones demonstrated that a concentration of 10 milligrams per millilitre of Sodium Fluoride in whole blood would increase the concentration of Ethanol in the head space vial by 8.9%. [Jones AW.(1983)…. When I carried out similar experiments using Methanol as the internal standard an apparent rise in the alcohol concentration of about 7% was found when only 0.5 millilitres of sample was added to the RTA vial as compared to the recommended volume. This was because the salting-out effect is greater for Ethanol than it is for Methanol in the head space vial. It has been suggested in the scientific literature, again by Professor A.W. Jones [(Jones AW). Salting-out effect of sodium chloride and its influence on the analysis of Ethanol by head space gas chromatography. Journal of Analytical Toxicology. 18 (5) : 292-3, 1994] that the salting-out phenomenon can be minimalised by diluting the sample and internal standard ten fold in the head space vial to reduce salting-out effects. In fact, the data he presented demonstrate that the salting-out effect is not, in fact, totally abolished by this technique. ”